1. Field of the Invention
The present invention generally relates to an image forming system comprising an image forming apparatus, and a post-processing apparatus for performing post-processing on a sheet after image formation. More particularly, the present invention relates to a technology for binding a sheet bundle formed of a plurality of sheets such as paper having an image formed thereon.
2. Description of the Related Art
Image forming systems may include a post-processing apparatus for performing various kinds of post-processing on a sheet having an image formed thereon by an image forming apparatus. As this type of post-processing apparatus, for example, there is known a sheet binding processing apparatus including a stapler for binding a sheet bundle formed of a plurality of sheets through a use of a binding member such as a metal staple.
In a sheet binding processing apparatus, generally, the sheet bundle delivered from the image forming apparatus is automatically bound by the stapler (“automatic stapling”). On the other hand, there is a demand to bind the sheet bundle through a manual operation by a user (“manual stapling”) instead of the automatic stapling.
To meet the users' demand as described above, U.S. Pat. No. 7,407,156B2 discloses such a technology that the user manually inserts the sheet bundle through a delivery port of the post-processing apparatus, to thereby bind the sheet bundle with the stapler.
In the technology disclosed in U.S. Pat. No. 7,407,156B2, when the manual stapling is performed, the user needs to insert the sheet bundle through the delivery port provided in a side of the post-processing apparatus. Therefore, it is desired to improve an operability of the sheet binding processing apparatus. From the viewpoint of improving the operability, it is conceived that the insertion port for the sheet bundle is arranged in a front surface of the post-processing apparatus, which is highly accessible to the user. In such a configuration, when one position of a corner of the sheet bundle is bound, it is not necessary to insert the sheet bundle in the deep part of the post-processing apparatus. Instead, by simply inserting a part of the sheet bundle in the insertion port provided in a front surface of the post-processing apparatus, the manual stapling can be performed.
In the configuration as described above, however, the position at which the stapler stands by (standby position) for binding the sheets becomes a problem. Generally, one stapler is provided in the post-processing apparatus. Through the movement of the stapler by a shifting mechanism, the sheet bundle can be bound at various positions by the post-processing apparatus. Taking into consideration of the fact that a print job including an instruction to bind the sheet is performed, the standby position of the stapler is set to a position different from the position for manual stapling. Therefore, when manual stapling is performed, the user needs to wait during a period in which the stapler is moved to a predetermined position.